Process of producing polymeric materials



- Patented Aug. 29, 1944.

PROCESS OF PRODUCING POLYMERIC MATERIALS Edward L. Krona, Old Greenwich, Conn., assignor to American Cyanamid Company, New York, N. Y., a corporation of Maine No Drawing. Application April 26, 1940,

.Serial No. 331,156

7 Claims.

This invention relates to the production of thermoplastic polymeric materials.

The use of polymers of various unsaturated substances has previously been somewhat limited because suitable solvents for many such substances and the polymers thereof have not been known. One of these, polyacrylonitrile, is insoluble in most of the known solvents. Accordingly, this material, as well as many of the other polymeric materials produced from unsaturated compounds, has not attained any substantial commercial utilization in the production of artificial fibers, films, etc.

Previously polymerization of unsaturated compounds has been carried out in a variety of organic solvents. In certain instances aqueous emulsions have been employed. In both instances, solutions or suspensions have been formed.

An object of this invention is to provide a solvent material and to so polymerize various unsaturated materials such as acrylonitrile, that concentrated solutions of the polymeric material thus produced may be obtained.

- Another object of this invention is to produce solutions of polymeric materials suitable for the production of artificial'fibers, films, etc.

Still another object of this invention is to polymerize unsaturated materials in salt solutions from which the polymer may be precipitated.

These and other objects are attained by polymerizing in an aqueous solution of a zinc salt which is extremely water-soluble, a substance of the following general formula:

, R CHz=R1 and isomers thereof, where R is hydrogen or methyl, where R1 may be CN or where R; is hydrogen, alkyl, alkaryl, cycloakyl, or

Example 1 Parts Zinc chloride 72 Water 18 Acrylonitrile 10 Benzoyl peroxide 0.002

To a solution of the zinc chloride in the water, the acrylonitrile with the benzoyl peroxide dissolved therein is added. heated at about C. for 4-5 hours during which time the solution changes to a thick viscous mass.

- This viscous mass is poured into a relatively large volume of water, thereby precipitating a polymeric powder. This powder may be separated by filtration, washed with water and dried. This dried material may be subjected to heat and pressure to produce molded articles having excellent chemical resistance and also being very resistant to heat. The dried powder may also be sheeted on hot mill rolls (e. g. C.) to yield tough clear films.

The filtrate which contains the zinc chloride may be concentrated in any suitable apparatus by heating at about 100 C. for suflicient time to volatilize enough water so that the concentrate is again suitable for re-use in polymerizing another batch of acrylonitrile or other polymerizable ma- .terial.

Example 2 Parts Acrylonitrile 8 Zinc chloride 74 Water 18 The acrylonltrile is mixed with a solution of the zinc chloride in the water. This solution becomes slightly warm during mixing. It is heated for about 5 hours at 90 C. and then aged for about 2 weeks at room temperature to increase the viscosity thereof.

Th solution may be extruded through a nozzle or spinneret whose internal diameter is approximately 0.1 millimeter. ably extruded into warm water (70-80 C.) under a pressure of about 35-40 pounds per square inch. Under these conditions a fiber is formed and c0- agulated which may be drawn at approximately 40 feet per minute. Utilizing somewhat lower temperatures, i. e., 67 C. and a pressure of about pounds per square inch a fiber is formed which may be drawn at about 30 feet per minute.

In order to increase the strength of the fibers produced it is desirable that they be drawn in such a manner that they will be stretched to a substantial extent. This may be conveniently This composition is The material is prefer-- Example 3 p Parts 75% solution of zinc chloride in water 54 Acrylonitrlle 25 Benzoyl peroxide 0.1

The acrylonitrile is dissolved in the zinc chloride solution and the mixture becomes very warm, thereby indicating the possibility of a chemical reaction between the monomeric acrylonitrile and product maybe utilised in the same general manner as described in Examples 1 and 2.

80% solution or zinc chloride in water 100 the zinc chloride. The :benzoyl peroxide is added and the mixture is heated for about /2 hour at 90-95 C. A rubbery gel is obtained. This gel may be washed with hot water until substantially free of zinc chloride solution. The resulting composition, which resembles crepe rubber when hot, may be milled on hot rolls at about 150-160 C. to produce extremely tough transparent films.

Example 4 4 Parts Methacrolein 75% solution of zinc chloride in water 25 The methacrolein is dissolved in the zinc chloride solution and a few drops of t-butyl peroxide are added. A solid somewhat opaque gel is obtained after about 12 hours at room temperature. This may be oxidized to produce a water-soluble polymer.

Example 5 Parts Methacrolein 7 Acrylonitrile .7 75% solution of zinc chloride in water s 12 The methacrolein and acrylonitrile are dissolved in the zinc chloride solution and a few drops of t-butyl peroxide are added. Upon standing at room temperature .for about 12 hours, a clear yellow viscous material is obtained which may be molded or extruded in the same general man- The methyl acrylate is dissolved in the zinc chloride solution and a few milligrams of benzoyl peroxide are added thereto. The mixture is then exposed to'a source of ultra-violet light such as a mercury arc for about 2-3 hours. Optionally heat may be applied in the same general manner as described in the preceding examples in addition to, or instead of, ultra-violet radiation. The methyl acrylate polymerizes during this time and the product may be utilized in the same general manner as described in Examples 1 and 2.

Example 7 Parts Vinyl acetate 5 80% solution of zinc chloride in water 10 peroxide are added thereto.

J Example 8 Vinyl aceta 25 The vinyl acetate is dissolved in the zinc chloride solution and a few milligrams of benzoyl peroxide are added thereto. The mixture is then exposed to a source of ultra-violet light such as a mercury arc for about 2-3 hours. The vinyl acetate polymerizes during this time and the product may be utilized in the'same general manner as described in Examples 1 and 2.

Example 9 Parts Methyl methacrylate 5 solution of zinc chloride in water.. 10

The methyl methacrylate is dissolved in the zinc chloride solution and a few milligrams of benzoyl peroxide are added thereto,'thereby forming a slightly pink solution. The mixture is then 'exposed to a source of ultra-violet light such as a mercury are for about 2-3 hours. methacrylate polymerizes during this time and the product may be utilized in the same general manner as described in Examplesl and 2.

80% solution of zinc chloride in water 10 i The methyl itaconate is dissolved in the zinc chloride solution and a few milligramsof benzoyl The mixture is then exposed to a source of ultra-violet light such as a mercury arc tor about 5-8 hours. The methyl itaconate polymerizes during this time and the product may be utilized in the same eneral manner as described in Examples 1 and 2.

The acrylonitrile is dissolved in the zinc chloride solution and is polymerized by heating in the presence of a small proportion of benzoyl peroxide at about C. Ior-aboutan hour. A small proportion 01' a water-dispersible dye, e. g., Calco Brilliant Pigment Blue BN, is dispersed in the solution containing the polymerized acrylonitrile. The resulting composition is applied to cloth in the same general manner as in textile printing. The cloth is then immersed in water, thereby precipitating the resin and the color mater 11. The treated cloth shows no leaching of the color material upon washing with soap and hot water.

In some instances, it may be desirable to copolymerize two or more unsaturated materials of the type described above or one or thetype described above with some other reactive polymerizable material. For certain purposes it may be advantageous to use a substance containing an amide group, e. g., acrylamide. in order to incorporate in the polymer groups having an afllnity ior acidic dyes. Similarly acrylic acid might be used in the'co-polymer thereby giving it an atflnity for basic dyes.

'Other substances which may be polymerized in the same general manner as described above are methacrylonitrile, ethyl acrylate, propyl acrylate, butyl acrylate, ethyl methacrylate. propyl meth- Parts The methyl acrylate, butyl methacrylate, allyl acetate, methallyl acetate, methacrylamide, methyl vinyl ketone, etc. Obviously various mixtures of these substances or mixtures of these substances with any of those described in the above examples may be used in the same general manner as the indibe substituted for all or part of the benzoyl peroxide or t-butyl peroxide, e. g., lauroyl peroxide or cocoanut oil peroxide, stearyl peroxide, aluminum chloride, etc. A polymerization catalyst is not necessary since the zinc salt acts as a catalyst itself although the reaction goes much more slowly and therefore it is generally desirable to use polymerization catalysts as indicated in the above examples.

- It is to be noted that concentrated aqueous solutions of many substances which will dissolve the polymerizable materials inhibit polymerization and therefore are not suitable for use according to this invention. Examples of such substances are sodium thiocyanate, potassium thiocyanate, zinc thiocyanate, etc. These substances are such active polymerization inhibitors that in some instances they are especially useful in stabilizing substances such as acrylonitrile against polymerization. Small amounts of some of these materials, e. g., sodium thiocyanate and potassium thiocyanate, may be incorporated into ptentially polymerizable materials in order to stabilize them over relatively long periods of time. These substances are particularly suitable since they may be easily separated from the polymerizable material merely by distillation leaving the salt used as a residue.

Fillers and/or pigments may be mixed with the polymeric products to produce molding compositions. Examples of these are: wood flour, wood fiber, paper dust, clay, zein, glass wool, foliated glass, mica, granite dust, silk flock, cotton flock, steel wool, carborundum, paper, cloth, sand, titanium oxide, lithopone, lead oxide, chrome yellow, lead cyanamide, zinc cyanamide, etc.

Polymeric materials made according to my invention have a wide variety of applications. The solutions produced according to the above description may be extruded to form filaments, films, ribbons or tubes. They may be used in the manufacture of woven fabric, gaskets, electrical insulation, heat insulation, etc. The polymeric materials may be molded to form gaskets. packing glands, electrical insulators, novelties, etc. The polyacrylonitrile materials are particularly suitable for such purposes wherein it is desirable to have materials which are resistant to grease, organic solvents, water, heat, etc.

Obviously many modifications and variations may be made in the processes and compositions described above without departing from the spirit and scope of the invention as defined in the ap-' pended claims.

I claim:

1. A process which comprises polymerizing a substance selected from the group consisting of compounds of the following general formula and isomers thereof:

R CHF-R where R is selected from the group consisting of hydrogen and methyl, where R1 is selected from the group consisting of -CN and where R: is selected from the group consisting of hydrogen, alkyl, alkaryl, cycloalkyl and Ra and where R; and R4 are selected from the group consisting of hydrogen and organic radicals, in an aqueous solution containing at least of a zinc salt, said zinc salt being selected from the group consisting of zinc chloride, zinc bromide and zinc iodide.

2. A process which comprises polymerizing acrylonitrile in an aqueous solution containing at least 65% of a zinc salt, said zinc salt being selected from the group consisting of zinc chloride, zinc bromide and zinc iodide.

3. A process which comprises polymerizing acrylonitrile in an aqueous solution containing at least 65% of zinc chloride.

4. A process which comprises polymerizing acrylonitrile in an aqueous solution containing at least 65% of zinc bromide.

5. A process which comprises polymerizing acrylonitrile in an aqueous solution containing at least 65% of zinc iodide.

6. A composition produced according to the process of claim 3 comprising an aqueous solution containing at least 65% of zinc chloride and at least 101% of polyacrylonitrile.

7. A composition produced according to the process of claim 1 and comprising an aqueous solution containing at least 65% of zinc chloride and at least 10% of polymer of said substance mentioned in claim 1.

EDWARD L. KROPA. 

